Research on wheelchair structure design reducing the load on human body in railway car

摘要

The demand for the wheelchair has increased along with the aging society of recent years. However, there are a lot of reports. It is the user of the wheelchair fell acute pain, shake of head, alarm. Then, the author worked on the improvement of the dynamic characteristics of wheelchair at railway vehicle. The goal of this study is development of the configuration design method for the wheelchair. Under the condition of sudden stop of the railway vehicle, wheelchair user makes force to the joint for keeping the posture, the wheelchair might be redesign to decrease this excessive power. First of all, the dynamical model of the wheelchair and the human body in the train vehicle is derived. It is constructed by two-dimensional rigid body model with seven degree of freedom. Joint torque at each joint is calculated when the vehicle stop suddenly. In addition, frequency response functions upper and lower dynamic excitations was obtained. As a result, it is shown that the human body did not shake easily at 2.5(Hz) or more frequencies. Changing the wheelchair shape, the angle of the foot rest, the bearing surface, and the backrest of the wheelchair, the joint torque that affects to the head part of the human body model when stopping suddenly is reduced in 0.02(Nm). It is shown that it is effective in the dynamical load alleviation to the wheelchair user.